Silk yarn prepared from natural silk in the gum



Patented Feb. 4,

"UNITED STATES PATENT oFFicE' 2.029.969, I smx YARN rnaraann mom NAT RAL I SILK m 'rnr: GUM

' Leo waumam, Rowland a. Gale, at new G. Hawley, In, New York, N. Y.,v assignon to Waller-stein Company New York Inc., a corporation of 'No Drawing. Application April 2t, 1934.

.Serlal'No. 122.505

1 OlaiQa. (01. 111-53) The .present invention rggtes 'to the -prepara-' tion of yarns and threadsrom natural silk in gum. Raw silk as exported to this country from Japan and from other silk producing centers'consists of fine strands of the silk protein, fibroin,

' each of which is encased in a coating of the silk. 1

twist in a/proces's which is termed the 5B operation and then one or more of'tnese doubled filan'rentsmay he highly-twistedfrom 30 up to 8501- and the number of threads twisted together is "teristic oflers a substantial resistance to twisting.

more turns per inch to give a suitable yarn or fibre for knitting'orweaving purposes.

Although the sericin or g'um coating on the filaments advan ageously lends body to the fibroin,

v and properly taken off the cones, spindles, and/or quills during the textile-forming operation, with- -.out tendency toward-tangles, uneven tension and itis disadvantageous in that itgives a wiry characteristic to the filaments, which wiry' charac- This resistance increases as the amount of twist increased.- This wiry-qu lity of theindividual v silk filaments tends to cause kinking andpre-. vents a uniformpacking together of the filaments when twisted or thrown which uniform packingis-most desirable in the production of high gr'ad yarns. 1

when thetwisted yarns are to be utilized. for kmtt ng purposes, they are wound on frusto-conical shapes known to thetrade simply-as cones, tlus process being ordinarily known .as coningl 'Due to the wiry quality ofjthe, threads, however,

it is diificultto place these threads uniformly upon cones. and the thread upon being taken off the cone will not run smoothly therefrom, but I will rather tend to slip andjump off,- giving rise to tangles; This. necessitates frequentadjustments ofv the machine togetherwith attended stopping and loss of time'by the operator. And,moreover,,a. considerable lossof silk in the form of, wasteoccurs.-. 1 1 on the other hand, in the weaving industry, where the yarn for the filler orweft is placed upon suitable 'quills' 1'- bobbins, carried in the shuttles; it is most important to maintain a desirable ten'-' sion of-the filler-as it is placed in the sheds formed by the warp; Due to the wiry characteristics'of the natural silk yam carryingits sum, it is diificult to maintain this tension since the silk tends to readily slip and 'jump oif the quills and bobbins withjthe same disadvantageous eifects as occur in the knitting process, above described.

Some attempts have been made to alleviate this wiryproperty of the natural silk in gum by impregnating such silk with various combina' tions of soap and oils. In general, the more wiry the silk to be treated, the more soap and oil required, and itwas generally found diiiicult to place suflicient soap and oil in the silk to decrease or alleviate the wiry property in a. most satisfactory manner.

In addition an object of. the present invention is to provide 'a yarn which will most satisfactorily lend itself to winding, doubling, and twisting operations, which will belargely devoid of the objectionable wiry qualities of natural silk in gum,

' and which at the same time will not necessarily carry objectionable quantities of soap and oil.

Another object is toprovide improved knitting and, weaving processes, in which-assurance is had that the silk yarn or filaments may be uniformly other undesirable effects. Q

- Other objects will appear during the course of the following specification.

In accomplishing the above objects, it has been found that the property of the natural silk in gum may be 1 3 1y alleviated by impregnating the silk before the textile operations with a proteolytic enzyme preparation,-at 'such te'mperatures and pfi values that no substantial utilize amount of the gum is removable.

It has been found most desirable to soakingbaths at temperatures below 50 C and at pH values ranging'from 4 to 10. The period of impregnation may vary from 15 to minutes up to overnight or 18 hours depending on the enzyme concentration After the impregnation,- the silk fibres are preferably dehydrated me- -.chanically as much as possible, as by centrifuging the tendency toward kinkiness andunevenness willbe greatly'decreasedr 4 Inadditionthe laymost-satm factorily upon cones, quills, and/or bobbins, to give a uniform tension and to run off smoothly and evenly without slippage or tangling during the operation of the. textile machines.

The enzyme preparation is generally utilized in conjunction with soap and/or oils to insure proper penetration and lubrication.

Various protease preparations may be used in carrying out the process, such as protease preparations derived from micro-organisms which under suitable culture conditions develop proteolytic enzymes, as for instanoe,- preparations derived from Aspergillus oryzie, from cultivation of bacteria, such as B. mesentricus, B. mycoides, or B. subtilis, or Mucor delemai', Amylomyces,

Rouxii, Penecillium, and so forth. Other suit-' able proteolytic enzymes may be used, such as papain, bromelin, malt enzymes, trypsin, pancreatin or pepsin. Suitable mixtures of the above described enzymes may also be used.

As examples in carrying out the process, one may proceed as follows:

Example 1.100 pounds of raw silk arewill be understood that other penetrants can be used for efiecting this wetting-out such as ,a small amount of soap.

If the soaking period is increased, the amount of enzyme may be decreased, as for example, with overnight soaking only half as much enzyme is required.

Other suitable pH regulators, for instance,

sodimn carbonate or bicarbonate, or a mixture thereof, may be used instead of the sodium sulfite referred to.

Emulsions of common soaking oils, such as neats foot oil, may also be used in conjunction with enzymes.

The temperature at which this process is carried out may be advantageouslyrvaried with the time consumed in the operation, the nature or origin of the silk, the nature of the particular silk in the gum are soaked for 30 minutes at room I temperature in 400 pounds of water solution containing 5 pounds of papain, 4 pounds of sulfonated oil, 0.05 pound of potassium cyanide, and 2 pounds of mono-sodium phosphate. It is then centrifuged and air dried.

v Example 3,-100 pounds of 13/15 Japan white silk in the gum are soaked for 30 minutes at room temperature in 400 pounds of water solution containing 5 pounds of pancreatin, and 1 pound of sodium sulfite with suitable penetrants and oils. It is then centrifuged and air dried.

The yarns as prepared above may be most satisfactorily wound, doubled, twisted, knitted, and/or woven without the many disadvantages due to the wiry characteristics of the natural silk which soaking solely with oils and/or soap does not satisfactorily alleviate.

The present application is a continuation in part of copending application Serial No, 606,286, filed April 19, 1932, and is similar in subject matter to copending applications Serial No. 722,504 and Nos. 722,506 to 722,508 all inclusive, filed April 26, 1934,

The present application is particularly directed -to highly twisted yams of decreased kinkiness or tendency to snarl.

What is claimed is:

Highly twisted silk yarns for weaving and knitting, comprising natural silk in gum, said yarn being rendered more flexible and with lessened tendency toward kinkiness and unevenness by impregnation with a-proteolytic enzyme prepa- 

